Text extracted from www.nospec.com :
"Spec work is any kind of creative work, either partial or completed, submitted by designers to prospective clients before designers secure both their work and equitable fees. Under these conditions, designers will often be asked to submit work in the guise of a contest or an entry exam on existing jobs as a “test” of their skill. In addition, designers normally lose all rights to their creative work because they failed to protect themselves with a contract or agreement. The clients often use this freely-gained work as they see fit without fear of legal repercussion."
Coincidentally, many years ago, asking for a job at a picture framing shop, I realised how precarious illustration work conditions were — as compared with other professions. No one will ever hesitate over paying fifty percent in advance and the rest after completion of a framing work; but, unluckily, for illustration that is not the case.
For more information about the absurdity of spec practice visit www.nospec.com